1. Field of the Invention
The present invention relates to an image processing apparatus using a plurality of tomograms and a control method thereof.
2. Description of the Related Art
There is known a medical tomogram display system including a server which saves a plurality of medical tomogram groups each formed from a plurality of digital images, and an image application terminal which is connected to the server and uses medical tomograms transferred from the server. Recently, improved performance of various modalities provides higher-resolution medical images, and the amount of image data is increasing. This prolongs the image transfer time to the image application terminal from the server which saves image groups. A need exists to shorten the time required until an image becomes usable on the image application terminal.
Conventional methods currently exist to shorten the transfer time between the server and the image application terminal. For example, there is a method of shortening the transfer time by transferring an image group after data compression to decrease the data amount. Japanese Patent Laid-Open No. 2009-230755 (to be referred to as Reference 1) proposes a method of shortening the waiting time by changing the tomogram transfer order to preferentially transfer a tomogram to be used, instead of deciding the tomogram transfer order arbitrarily (e.g., file name order).
However, the data compression ratios are low for noisy images such as those captured by OCT (Optical Coherence Tomography). When the data compression time and data decompression time is considered, the transfer time taken to transfer a noisy image after data compression may become longer than that taken to perform the transfer without data compression. Depending on the image, data compression is sometimes ineffective for transfer processing. The method described in Reference 1 decides the input order in descending order of closeness to the slice position of a given tomogram. A waiting time is generated till the completion of input of a tomogram at a slice position spaced apart from the given tomogram. Even if a tomogram at the region of interest is to be used, it may not be used quickly because input of a required tomogram has not completed.